The crystal engineering of cytidine (Cyd), 2′-deoxycytidine (dCyd) and their phosphate salts Part 2. The mechanistic analysis of an easy transformation of two dCyd phosphate salts, mono- and hemi(dihydrogenphosphates), when in a crystal state, using thermochemical data, computer experiments and FT-IR-PAS spectra

Abstract The unexpectedly large differences in the thermochemical (DSC and TGA) properties of the isostructural crystalline mono(dihydrogenphosphate) salts of Cyd and dCyd encouraged us to propose a molecular mechanism of a hypothetical transformation of dCydH + cations into dimeric hemications (dCyd) 2 H + in the solid state, as well as the reverse transformation. The proposed mechanism has been experimentally confirmed and found to be consistent with a significant resistance to a similar transformation by the analogous salt of Cyd. Hence, new information is provided about the influence of the 2′ OH group on the association aptitude of ribo- and deoxyribonucleosides, nucleotides and their derivatives.